'use strict';

var _ = require('lodash');
var async = require('async');
var Mustache = require('mustache');
var defaultRequest = require('request');
var MessageBroker = require('./messagebroker');
var Storage = require('./storage');
var fs = require('fs');
var path = require('path');
var Utils = require('./common/utils');
var Model = require('./model');
var sjcl = require('sjcl');
var log = require('npmlog');
log.debug = log.verbose;

var PUSHNOTIFICATIONS_TYPES = {
  'NewCopayer': {
    filename: 'new_copayer',
  },
  'WalletComplete': {
    filename: 'wallet_complete',
  },
  'NewTxProposal': {
    filename: 'new_tx_proposal',
  },
  'NewOutgoingTx': {
    filename: 'new_outgoing_tx',
  },
  'NewIncomingTx': {
    filename: 'new_incoming_tx',
  },
  'TxProposalFinallyRejected': {
    filename: 'txp_finally_rejected',
  },
};

function PushNotificationsService() {};

PushNotificationsService.prototype.start = function(opts, cb) {
  var self = this;
  opts = opts || {};
  self.request = opts.request || defaultRequest;

  function _readDirectories(basePath, cb) {
    fs.readdir(basePath, function(err, files) {
      if (err) return cb(err);
      async.filter(files, function(file, next) {
        fs.stat(path.join(basePath, file), function(err, stats) {
          return next(!err && stats.isDirectory());
        });
      }, function(dirs) {
        return cb(null, dirs);
      });
    });
  };

  self.templatePath = path.normalize((opts.pushNotificationsOpts.templatePath || (__dirname + '/templates')) + '/');
  self.defaultLanguage = opts.pushNotificationsOpts.defaultLanguage || 'en';
  self.defaultUnit = opts.pushNotificationsOpts.defaultUnit || 'btc';
  self.subjectPrefix = opts.pushNotificationsOpts.subjectPrefix || '';
  self.pushServerUrl = opts.pushNotificationsOpts.pushServerUrl;
  async.parallel([

    function(done) {
      _readDirectories(self.templatePath, function(err, res) {
        self.availableLanguages = res;
        done(err);
      });
    },
    function(done) {
      if (opts.storage) {
        self.storage = opts.storage;
        done();
      } else {
        self.storage = new Storage();
        self.storage.connect(opts.storageOpts, done);
      }
    },
    function(done) {
      self.messageBroker = opts.messageBroker || new MessageBroker(opts.messageBrokerOpts);
      self.messageBroker.onMessage(_.bind(self._sendPushNotifications, self));
      done();
    },
  ], function(err) {
    if (err) {
      log.error(err);
    }
    return cb(err);
  });

};

PushNotificationsService.prototype._sendPushNotifications = function(notification, cb) {
  var self = this;
  cb = cb || function() {};

  var notifType = PUSHNOTIFICATIONS_TYPES[notification.type];
  if (!notifType) return cb();

  log.debug('Notification received: ' + notification.type);
  log.debug(JSON.stringify(notification));

  self._checkShouldSendNotif(notification, function(err, should) {
    if (err) return cb(err);

    log.debug('Should send notification: ', should);
    if (!should) return cb();

    self._getRecipientsList(notification, function(err, recipientsList) {
      if (err) return cb(err);

      async.waterfall([

        function(next) {
          self._readAndApplyTemplates(notification, notifType, recipientsList, next);
        },
        function(contents, next) {
          async.map(recipientsList, function(recipient, next) {
            var opts = {};
            var content = contents[recipient.language];
            opts.users = [notification.walletId + '$' + recipient.copayerId];
            opts.android = {
              "data": {
                "title": content.plain.subject,
                "message": content.plain.body,
                "walletId": sjcl.codec.hex.fromBits(sjcl.hash.sha256.hash(notification.walletId)),
                "notId": Math.floor(Math.random() * 100000) + 1
              }
            };
            opts.ios = {
              "alert": {
                "title": content.plain.subject,
                "body": content.plain.body
              },
              "sound": "default",
              "payload": {
                "walletId": sjcl.codec.hex.fromBits(sjcl.hash.sha256.hash(notification.walletId))
              }
            };
            return next(err, opts);
          }, next);
        },
        function(optsList, next) {
          async.each(optsList,
            function(opts, next) {
              self._makeRequest(opts, function(err, response) {
                if (err) log.error(err);
                if (response) {
                  log.debug('Request status: ', response.statusCode);
                  log.debug('Request message: ', response.statusMessage);
                  log.debug('Request body: ', response.request.body);
                }
                next();
              });
            },
            function(err) {
              return next(err);
            }
          );
        },
      ], function(err) {
        if (err) {
          log.error('An error ocurred generating notification', err);
        }
        return cb(err);
      });
    });
  });
};

PushNotificationsService.prototype._checkShouldSendNotif = function(notification, cb) {
  var self = this;

  if (notification.type != 'NewTxProposal') return cb(null, true);
  self.storage.fetchWallet(notification.walletId, function(err, wallet) {
    return cb(err, wallet.m > 1);
  });
};

PushNotificationsService.prototype._getRecipientsList = function(notification, cb) {
  var self = this;

  self.storage.fetchWallet(notification.walletId, function(err, wallet) {
    if (err) return cb(err);

    self.storage.fetchPreferences(notification.walletId, null, function(err, preferences) {

      if (err) log.error(err);
      if (_.isEmpty(preferences)) preferences = [];

      var recipientPreferences = _.compact(_.map(preferences, function(p) {

        if (!_.contains(self.availableLanguages, p.language)) {
          if (p.language)
            log.warn('Language for notifications "' + p.language + '" not available.');
          p.language = self.defaultLanguage;
        }

        return {
          copayerId: p.copayerId,
          language: p.language,
          unit: p.unit,
        };
      }));

      recipientPreferences = _.indexBy(recipientPreferences, 'copayerId');

      var recipientsList = _.reject(_.map(wallet.copayers, function(copayer) {
        var p = recipientPreferences[copayer.id] || {};
        return {
          copayerId: copayer.id,
          language: p.language || self.defaultLanguage,
          unit: p.unit || self.defaultUnit,
        }
      }), {
        copayerId: notification.creatorId
      });

      return cb(null, recipientsList);
    });
  });
};

PushNotificationsService.prototype._readAndApplyTemplates = function(notification, notifType, recipientsList, cb) {
  var self = this;

  async.map(recipientsList, function(recipient, next) {
    async.waterfall([

      function(next) {
        self._getDataForTemplate(notification, recipient, next);
      },
      function(data, next) {
        async.map(['plain', 'html'], function(type, next) {
          self._loadTemplate(notifType, recipient, '.' + type, function(err, template) {
            if (err && type == 'html') return next();
            if (err) return next(err);

            self._applyTemplate(template, data, function(err, res) {
              return next(err, [type, res]);
            });
          });
        }, function(err, res) {
          return next(err, _.zipObject(res));
        });
      },
      function(result, next) {
        next(null, result);
      },
    ], function(err, res) {
      next(err, [recipient.language, res]);
    });
  }, function(err, res) {
    return cb(err, _.zipObject(res));
  });
};

PushNotificationsService.prototype._getDataForTemplate = function(notification, recipient, cb) {
  var self = this;
  var UNIT_LABELS = {
    btc: 'BTC',
    bit: 'bits'
  };

  var data = _.cloneDeep(notification.data);
  data.subjectPrefix = _.trim(self.subjectPrefix + ' ');
  if (data.amount) {
    try {
      var unit = recipient.unit.toLowerCase();
      data.amount = Utils.formatAmount(+data.amount, unit) + ' ' + UNIT_LABELS[unit];
    } catch (ex) {
      return cb(new Error('Could not format amount', ex));
    }
  }

  self.storage.fetchWallet(notification.walletId, function(err, wallet) {
    if (err) return cb(err);

    data.walletId = wallet.id;
    data.walletName = wallet.name;
    data.walletM = wallet.m;
    data.walletN = wallet.n;

    var copayer = _.find(wallet.copayers, {
      id: notification.creatorId
    });

    if (copayer) {
      data.copayerId = copayer.id;
      data.copayerName = copayer.name;
    }

    if (notification.type == 'TxProposalFinallyRejected' && data.rejectedBy) {
      var rejectors = _.map(data.rejectedBy, function(copayerId) {
        return _.find(wallet.copayers, {
          id: copayerId
        }).name
      });
      data.rejectorsNames = rejectors.join(', ');
    }

    return cb(null, data);
  });
};

PushNotificationsService.prototype._applyTemplate = function(template, data, cb) {
  if (!data) return cb(new Error('Could not apply template to empty data'));

  var error;
  var result = _.mapValues(template, function(t) {
    try {
      return Mustache.render(t, data);
    } catch (e) {
      log.error('Could not apply data to template', e);
      error = e;
    }
  });

  if (error) return cb(error);
  return cb(null, result);
};

PushNotificationsService.prototype._loadTemplate = function(notifType, recipient, extension, cb) {
  var self = this;

  self._readTemplateFile(recipient.language, notifType.filename + extension, function(err, template) {
    if (err) return cb(err);
    return cb(null, self._compileTemplate(template, extension));
  });
};

PushNotificationsService.prototype._readTemplateFile = function(language, filename, cb) {
  var self = this;

  var fullFilename = path.join(self.templatePath, language, filename);
  fs.readFile(fullFilename, 'utf8', function(err, template) {
    if (err) {
      return cb(new Error('Could not read template file ' + fullFilename, err));
    }
    return cb(null, template);
  });
};

PushNotificationsService.prototype._compileTemplate = function(template, extension) {
  var lines = template.split('\n');
  if (extension == '.html') {
    lines.unshift('');
  }
  return {
    subject: lines[0],
    body: _.rest(lines).join('\n'),
  };
};

PushNotificationsService.prototype._makeRequest = function(opts, cb) {
  var self = this;

  self.request({
    url: self.pushServerUrl + '/send',
    method: 'POST',
    json: true,
    body: opts
  }, function(err, response) {
    return cb(err, response);
  });
};

module.exports = PushNotificationsService;